A) After Rumple’s confrontation with his father that sets in motion a series of events that triggers a facet of the curse.
Agreed. Killing Pan somehow has consequences outside of whatever it might mean for the Dark One, since Rumple uses his dagger
Lana tweeted a while back that Regina’s heart will brighten again, it’s possible that Emma, Henry and the rest of the gang have Regina’s true self in sight but since Regina is linked to the darkness it won’t relinquish her w/o a fight and in order to spare Henry whatever, evil that curse may cause her to do she exiles herself to the forest prompting a rescue mission that involves a detour to NYC for some reason. And when the heroes arrive in the Forest the curse makes them look as they did before.
“The Darkness likes the way you taste.” If Regina is going to be apart from everyone, I would prefer it be of her own choosing and not some magical separation tactic.
C) Emma and Henry get stranded in Storybrooke with the challenge of reuniting everyone maybe while facing down remnants of that network Pan had created (Greg, Tamara, John & Michael may not be the only ones)
Yes I doubt that GOAT and the Darlings Bros are the only members of the Home Office. We know, for example, that Tamara had the red potion the Dragon gave her sent out for analysis so there has to be a more science-y division in the world somewhere.